Indo-Pacific Finless Porpoise

The Indo-Pacific finless porpoise is a small, rounded cetacean with no dorsal fin. A low ridge bearing rows of tubercles runs along the back, while the head is blunt and lacks a beak. It inhabits shallow tropical and subtropical coasts from the northern Indian Ocean into the western Pacific, including estuaries and mangrove-lined channels. (Wikipedia, general species account)

It eats fish, cephalopods and crustaceans and normally occurs alone or in small groups. Surfacing is quiet and rolling, with little splashing, making it easy to overlook despite its preference for nearshore water. (Wikipedia, general species account)